<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>加减法口算练习系统-v0.1</title>
    <style>
        body { font-family: Arial, sans-serif; max-width: 800px; margin: 0 auto; padding: 20px; }
        h1 { color: #333; text-align: center; }
        .exercise-container { margin-top: 30px; }
        .exercise { font-size: 18px; margin: 10px 0; padding: 8px; border-bottom: 1px solid #eee; }
        .column { float: left; width: 50%; }
        @media (max-width: 600px) {
            .column { width: 100%; }
        }
    </style>
</head>
<body>
    <h1>加减法口算练习系统-v0.1</h1>
    <div class="exercise-container">
        <div class="column">
            <div class="exercise">1. 28 - 27 = </div>
            <div class="exercise">2. 95 - 44 = </div>
            <div class="exercise">3. 77 - 77 = </div>
            <div class="exercise">4. 33 - 19 = </div>
            <div class="exercise">5. 47 + 39 = </div>
            <div class="exercise">6. 89 - 0 = </div>
            <div class="exercise">7. 85 - 9 = </div>
            <div class="exercise">8. 28 - 14 = </div>
            <div class="exercise">9. 79 - 70 = </div>
            <div class="exercise">10. 48 + 2 = </div>
            <div class="exercise">11. 55 - 3 = </div>
            <div class="exercise">12. 40 - 7 = </div>
            <div class="exercise">13. 37 + 49 = </div>
            <div class="exercise">14. 59 - 34 = </div>
            <div class="exercise">15. 61 - 17 = </div>
            <div class="exercise">16. 80 - 77 = </div>
            <div class="exercise">17. 74 + 12 = </div>
            <div class="exercise">18. 98 - 45 = </div>
            <div class="exercise">19. 90 - 29 = </div>
            <div class="exercise">20. 38 - 14 = </div>
            <div class="exercise">21. 7 + 91 = </div>
            <div class="exercise">22. 73 - 56 = </div>
            <div class="exercise">23. 87 - 77 = </div>
            <div class="exercise">24. 68 - 50 = </div>
            <div class="exercise">25. 47 - 20 = </div>
        </div>
        <div class="column">
            <div class="exercise">26. 69 - 58 = </div>
            <div class="exercise">27. 78 - 60 = </div>
            <div class="exercise">28. 68 - 12 = </div>
            <div class="exercise">29. 56 - 41 = </div>
            <div class="exercise">30. 50 - 10 = </div>
            <div class="exercise">31. 84 - 39 = </div>
            <div class="exercise">32. 78 - 68 = </div>
            <div class="exercise">33. 66 - 6 = </div>
            <div class="exercise">34. 83 - 22 = </div>
            <div class="exercise">35. 62 - 44 = </div>
            <div class="exercise">36. 64 - 48 = </div>
            <div class="exercise">37. 78 - 18 = </div>
            <div class="exercise">38. 37 + 13 = </div>
            <div class="exercise">39. 34 - 27 = </div>
            <div class="exercise">40. 93 - 31 = </div>
            <div class="exercise">41. 30 + 26 = </div>
            <div class="exercise">42. 99 - 42 = </div>
            <div class="exercise">43. 7 + 53 = </div>
            <div class="exercise">44. 76 - 62 = </div>
            <div class="exercise">45. 44 - 44 = </div>
            <div class="exercise">46. 81 - 8 = </div>
            <div class="exercise">47. 14 - 10 = </div>
            <div class="exercise">48. 93 - 42 = </div>
            <div class="exercise">49. 32 + 38 = </div>
            <div class="exercise">50. 97 - 76 = </div>
        </div>
    </div>
</body>
</html>
